Go to the main menu
Skip to content
Go to bottom
REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
> Journal Vol & Issue
Transactions of Materials Processing
Journal Basic Information
Journal DOI :
The Korean Society for Technology of Plasticity
Editor in Chief :
Volume & Issues
Volume 24, Issue 6 - Dec 2015
Volume 24, Issue 5 - Oct 2015
Volume 24, Issue 4 - Aug 2015
Volume 24, Issue 3 - Jun 2015
Volume 24, Issue 2 - Apr 2015
Volume 24, Issue 1 - Feb 2015
Selecting the target year
A Study of the Shearing Force as a Function Trim Punch Shape and Shearing Angle
Yoo, C.K. ; Won, S.T. ;
Transactions of Materials Processing, volume 24, issue 2, 2015, Pages 77~82
DOI : 10.5228/KSTP.2015.24.2.77
By investigating the practical use of trim punch configurations for shearing of vehicle panels, the current study first reviews the shearing angle as part of the shearing die design. Based on this review, four different types of trim punch shapes (i.e., horizontal, slope, convex, and concave type) and shearing angles(i.e., 0.76°, 1.53°, 2.29°, 3.05°, 3.81°) were investigated. In order to conduct shearing experiments, four types of trim punch dies were made. The four trim punch dies were tested under various conditions. The experiments used the four trim punch shapes and the five shearing angles. The shearing force varied by shape and decreased from horizontal, slope, convex, to concave for the same shearing angle. The magnitude of shearing force showed differences between the convex and the concave shapes due to the influence of constrained shearing versus free shearing. The test results showed that compared to the horizontal trim punch shearing force, the decrease of the slope, convex, and concave shearing forces were 22.6% to 60.4%. Based on the results, a pad pressure of over 30% is suggested when designing a shearing die.
A Study of High Viscosity Phosphor Dispensing for an Electrostatic Printing System
Kim, S.W. ; Yang, Y.J. ; Dang, H.W. ; Yang, B.S. ; Kim, H.B. ; Choi, K.H. ;
Transactions of Materials Processing, volume 24, issue 2, 2015, Pages 83~88
DOI : 10.5228/KSTP.2015.24.2.83
For chromaticity correction, it is necessary to dispense high viscosity phosphor slurry since it greatly affects the performance of white LEDs. However, it is quite difficult to dispense high viscosity fluorescent materials. In the current study, micro-discharge electrostatic printing has been used for dispensing various high viscosity phosphor slurries. We have achieved dispersions of up to 50 µg using drop on demand (DOD) discharge experiments. The experiments were conducted with different combinations of process variables such as applied voltage, pneumatic pressure, and frequency.
Flow Analysis of Resin in an Extrusion Die for the Production of Medical Catheter Tubes
Lee, M.A. ; Lyu, M.-Y. ; Shin, D.J. ; Kim, T.K. ;
Transactions of Materials Processing, volume 24, issue 2, 2015, Pages 89~94
DOI : 10.5228/KSTP.2015.24.2.89
Medical catheter tubes are disposable devices that are inserted into the body cavities such as the pleura, trachea, esophagus, stomach, urinary bladder, ureter, or blood vessels for surgical procedures. Each hole of the inner tube is called a lumen, which is used as a passage for drug injections, waste discharge, polypus removal, blood transport, or injection of a camera or sensor. The catheter tube is manufactured by extrusion. The flow in the inner extrusion die affects the thickness and diameter of the tube. In the current study computer simulation of flow in an extrusion die for catheter tubing was performed. Velocity, pressure, shear rate, and shear stress were investigated and the die design was examined.
The Effect of Squeezing Parameters on the Fabrication Behavior of Phosphor Films
Park, J.Y. ; Lee, J.W. ; Yoon, G.S. ;
Transactions of Materials Processing, volume 24, issue 2, 2015, Pages 95~100
DOI : 10.5228/KSTP.2015.24.2.95
It was confirmed that when phosphor slurry is formed in the cavity of an elastic mold, the pressure distribution of the phosphor slurry varies as a function of the major squeegee parameters (squeegee angle, squeegee velocity, and the viscosity of the phosphor slurry). The higher the slurry viscosity, the faster the squeegee velocity, and the smaller the squeegee angle, the higher the filling completeness of the phosphor slurry. The optimum conditions for complete filling of the phosphor slurry were found when the squeegee angle was between 30 to 45 degrees, squeegee velocity at 40 to 70mm/sec, and the viscosity of the phosphor slurry composite was at 6,556 cps (i.e. phosphor content around 50 wt. %).
Cure and Heat Transfer Analysis in LED Silicone Lens using a Dynamic Cure Kinetics Method
Song, M.J. ; Kim, K.H. ; Hong, S.K. ; Park, J.Y. ; Lee, J.W. ; Yoon, G. S. ;
Transactions of Materials Processing, volume 24, issue 2, 2015, Pages 101~106
DOI : 10.5228/KSTP.2015.24.2.101
Recently, silicone is being used for LED chip lens due to its good thermal stability and optical transmittance. In order to predict residual stresses, which cause optical birefringence and mechanical warpage of silicone, a finite element analysis was conducted for the curing of silicone during molding. For the analysis of the curing process, a dynamic cure kinetics model was derived based on the results of a differential scanning calorimetry (DSC) testing and applied to the material properties for finite element analysis. Finite element simulation results showed that a step cure cycle reduced abrupt reaction heat and showed a decrease in the residual stresses.
Measurement and Analysis of the Section Profile for Feature Line Surface on an Automotive Outer Panel
Choe, W.C. ; Chung, Y.C. ;
Transactions of Materials Processing, volume 24, issue 2, 2015, Pages 107~114
DOI : 10.5228/KSTP.2015.24.2.107
The current study presents a geometric measurement and analysis of the section profile for a feature line surface on an automotive outer panel. A feature line surface is the geometry which is a visually noticeable creased line on a smooth panel. In the current study the section profile of a feature line surface is analyzed geometrically. The section profile on the real press panel was measured using a coordinate measuring machine. The section profiles from the CAD model and the real panel are aligned using the same coordinate system defined by two holes near the feature line. In the aligned section profiles the chord length and height of the curved part were measured and analyzed. The results show that the feature line surface on the real panel is doubled in width size.
Dimensional Accuracy of Cylindrical Cups in Multi-Stage Drawing of Aluminum Sheet Metal
Choi, J.M. ; Kim, J.H. ;
Transactions of Materials Processing, volume 24, issue 2, 2015, Pages 115~120
DOI : 10.5228/KSTP.2015.24.2.115
Deep drawing of cylindrical cups is one of the most fundamental and important processes in sheet metal forming. Circular cups are widely used in industrial fields such as automobile and electronic appliances. Some of these cups are formed by a one-stage process, others such as battery cases and beverage cans are made by a multi-stage process. In the current study the multi-stage deep drawing of aluminum sheet metal is examined. The process consists of two deep drawing operations followed by two ironing operations. The press die, which can be used for the four-stage forming process, was manufactured allowing punch and die components to be easily changed for various experiments. The rolling direction of both the sheet and the drawn cups was always positioned toward the horizontal x-direction on the die face to minimize experimental errors during the progressive forming. The dimensional accuracy of the cylindrical cups formed at each stage and the earing defect due to the anisotropy of sheet were investigated. The influence of anisotropy on the thickness distribution was also examined. Both the thickness and the outer diameter of the cups were measured and compared for each set of experimental conditions. It was found that the dimensional accuracy of cups rapidly improves by employing the ironing process and also by increasing the amount of ironing.
A Study of STS 316L Threaded Elbow Fitting Fabrication by Metal Injection Molding
Kim, J.Y. ; Kim, S.J. ; Chung, S.T. ; Ahn, S. ;
Transactions of Materials Processing, volume 24, issue 2, 2015, Pages 121~129
DOI : 10.5228/KSTP.2015.24.2.121
A net-shape forming of small and complex-shaped metal parts by metal injection molding (MIM) has economic advantages in mass production, especially for STS 316L valve fitting. STS 316L offers excellent corrosion resistance, but it has poor machinability, which is a limitation in using it for a cost-effective production where both forging and machining are employed. Simulation and experimental analysis were performed to develop a MIM STS 316L 90° elbow fitting minimizing trial and error. A Taguchi method was used to determine which input parameter was the most sensitive to possible defects (e.g. sink mark depth) during the injection molding. The final prototype was successfully built. The results indicate that the simulation tool can be used during the design process to minimize trial and error, but the final adjustment of parameters based on field experience is essential.
Development Process of Side Impact Beam for Automotive Light-Weighting Door using Sheet Type
Lee, I.C. ; Lee, T.K. ; Jang, D.H. ;
Transactions of Materials Processing, volume 24, issue 2, 2015, Pages 130~137
DOI : 10.5228/KSTP.2015.24.2.130
This paper presents the development process of automotive side door impact beam for passenger cars. Weight reduction while maintaining functional requirements is one of the major goals in the automotive industry. In this study, thin-walled side door beam using quenchable boron steel was designed to reduce the weight of conventional side door tubular one. In order to estimate design for the proposed side door beams, the static side impact protection tests(FMVSS 214) were conducted using the finite element method. Based on the simulation results, geometry modification of the side door beam has been performed via creating new reinforcing ribs. Furthermore, the manufactured frontal impact beam was mounted on the real side door of a passenger car, and then static impact protection test carried out. It is concluded that the presented test results can provide significant contribution to the stiffness of side door impact beams and light-weighting door research.
Die Materials and their Wear Evaluation for Press Forming of High Strength Steels
Kim, Y.S. ; Park, K.C. ; Nam, J.B. ; Lee, B.H. ;
Transactions of Materials Processing, volume 24, issue 2, 2015, Pages 138~146